(I have no clue if this is true or not)

In ancient England people could not have sex unless they had consent of the king (unless they were in the Royal Family ).
When people wanted to have a baby, they had to get the consent of the king, and the king gave them a placard that they hung on their door while they were having sex.
The placard had F.U.C.K. (Fornication Under Consent of the King ) on it .
Hence that's where the word FUCK came from.
Now, aren't you glad you learned something new today ?